In the field of entrained flow gasification two types of gasification reactors have been developed, namely the types as described in for example U.S. Pat. No. 4,202,672, U.S. Pat. No. 6,312,482 and DE-A-2425962, and types as for example described in U.S. Pat. No. 5,968,212 and US-A-2001/0020346. Both reactor type have a combustion chamber into which a burner discharges a product gas comprising hydrogen and carbon monoxide. The gasification reactors of the first type have a product gas outlet at the upper end of the, in use, combustion chamber and an opening for discharge of slag, at the opposite, lower end of the combustion chamber. The second type of reactor has a combined outlet for both product gas and slag at the, in use, lower end of the combustion chamber. The invention is directed to an improved gasification reactor of the second type.
U.S. Pat. No. 5,968,212 describes a gasification reactor provided at its upper end with a downwardly directed burner. The reactor is also provided with a combustion chamber. The wall of the combustion chamber is made up of a refractory grade lining. The product gas leaving the opening in the lower end of the combustion chamber may enter a lower part of the reactor which part is provided with a waste heat boiler.
US-A-2001/0020346 discloses a gasification reactor provided at its upper end with a downwardly directed burner. The reactor is also provided with a combustion chamber. The wall of the combustion chamber comprises an arrangement of vertical and parallel-arranged tubes placed on the interior of the reactor wall. According to this publication, a protective layer of slag will form on the wall of the combustion chamber when an ash-containing feed is used as feed for the gasification reactor. The caked layer of slag will be responsible for the thermal insulation between the combustion chamber and the tubes. According to this publication, such a slag layer will not be formed if a low-ash feed is used. In such a situation, according to US-A-2001/0020346, a lining of refractory brickwork is to be used.
A disadvantage of having to use a refractory brickwork when feeding to said gasification reactor a low-ash feed is that the lifetime of the refractory brickwork is low. It appears that the operational temperature window of a refractory layer of this type is very limited. Temporarily high gas temperatures, as can be the case in an upset situation, will damage and dissolve the refractory. This could happen even if the ash content in the feed is very low.
The object of the present invention is to provide a gasification reactor, which can run on any feed for a prolonged period of time, even if the ash content is very low.